Prospective evaluation of ultra-low-dose contrast-enhanced 100-kV abdominal computed tomography with tin filter: effect on radiation dose reduction and image quality with a third-generation dual-source CT system.

OBJECTIVES: To investigate the radiation dose exposure, image quality, and diagnostic performance of enhanced 100-kVp abdominopelvic single-energy CT protocol with tin filter (TF). METHODS: Ninety-three consecutive patients referred for a single-phase enhanced abdominopelvic CT were prospectively included after informed consent. They underwent in addition to a standard protocol (SP) an acquisition with TF. Both examinations were performed on a third-generation dual-source CT system (DSCT), in single energy, using automatic tube current modulation, identical pitch, and identical level of iterative reconstruction. Radiation metrics were compared. Size-specific dose estimates (SSDE), contrast to noise ratio (CNR), and figure of merit (FOM) were calculated. Diagnostic confidence for the assessment of a predetermined list of abdominal lesions was rated by two independent readers. RESULTS: The mean dose of the TF protocol was significantly lower (CDTI 1.56 ± 0.43 mGy vs. 8.13 ± 3.32, p < 0.001; SSDE 9.94 ± 3.08 vs. 1.93 ± 0.39, p < 0.001), with an effective dose close to 1 mSv (1.14 mSv ± 0.34; p < 0.001). TF group exhibited non-significant lower liver CNR (2.76 vs. 3.03, p = 0.56) and was more dose efficient (FOM 10.6 vs. 2.49/mSv, p < 0.001) in comparison to SP. The mean diagnostic confidence for visceral, bone, and peritoneal tumors was equivalent between both groups. CONCLUSIONS: Enhanced 100-kVp abdominopelvic CT acquired after spectral shaping with tin filtration can achieve similar diagnostic performance and CNR compared to a standard CT protocol, while reducing the radiation dose by 81%. KEY POINTS: • 100-kVp spectral filtration enables enhanced abdominal CT with high-dose efficiency. • The radiation dose reaches the 1-mSv range. • Predetermined abdominopelvic lesions can be assessed without impairing on diagnostic confidence.

Rectal cancer treatment in a teaching hospital.

BACKGROUND: Rectal adenocarcinomas surgery morbidity and mortality might be impaired by neoadjuvant therapy. We performed this retropsective study to be compared with the PROCARE study running afterwards. METHODS: We performed a retrospective study of 95 patients operated on for rectal adenocarcinoma in a single institution during the period of 2007-2009. We used logistic regression to estimate the relationship between possible predictive parameters of anastomotic leakage (AL). RESULTS: The laparoscopic approach is favored in 63.1% of the cases with a conversion rate of 11.6%, mainly in man (6 out of 7). For low rectal cancer though, laparotomy was the first choice (92.3%). From a carcinological point of view, laparoscopy allowed a complete tumor resection according to the PME (n = 27) and TME (n = 26) standards. Multivariate analysis revealed that women, lower BMI, lower rectum tumor, laparoscopic surgery, neoadjuvant treatment and anal suture were associated with higher risk of AL. The mean hospital stay was 15.4 days (3-46 days) with an in-hospital mortality rate of 3.1%. Adjuvant chemotherapy was completed in 42.1% of the patients. Despite these treatments, we registered a recurrence rate of 26.6%. Of these, 72% were distally localized and 12% exclusively locally. Among the patients operated on by laparoscopy, there was one local recurrence and one local with distant metastases (3.7%). The one- and three-year survival rates were 91.5% and 80.4%, respectively. CONCLUSIONS: Our study showed a higher rate of AL than expected (18%). In our series recorded in PROCARE-Home, our leak rate has dropped to 10%. It may be indicating a positive effect of PROCARE.

MR imaging of iron phagocytosis in intraluminal thrombi of abdominal aortic aneurysms in humans.

PURPOSE: To prospectively determine if superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging could help visualize leukocyte phagocytic activities in human abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: This study was approved by the institutional ethics committee; all patients gave informed consent. Preoperative MR imaging data, including unenhanced and SPIO-enhanced T1-, T2*-, and T2-weighted transverse images of the entire AAA, obtained 1 hour after contrast enhancement from 15 patients (mean age, 72.7 years +/- 8.2; range, 60-83 years), 10 men (mean age, 73.5 years +/- 7.9; range, 60-83 years) and five women (mean age, 71.2 years +/- 9.4; range 60-82), were retrospectively evaluated. Morphologic appearance and semiquantitative and contrast-to-noise ratio (CNR) analyses of the thrombi were performed. Thrombi were analyzed semiquantitatively at microscopy after staining with hematoxylin-eosin, CD68, and CD66b. Levels of promatrix metalloproteinase (pro-MMP)-2 and pro-MMP-9, MMP-2 and MMP-9, and their mRNA located in the thrombus were assessed by using zymography and quantitative reverse transcriptase polymerase chain reaction analysis. Nonparametric statistics of the Spearman rank correlation were calculated to evaluate correlations between the aneurysm thrombus signal level decrease after SPIO and the levels of CD68(+), CD66b(+) cells, pro-MMP-2 and pro-MMP-9, MMP-2 and MMP-9, and MMP-9 mRNA. RESULTS: The pre-SPIO CNRs in the luminal sublayer of the thrombus and the deeper thrombus were -10.20 +/- 12.69 and -5.68 +/-10.38, respectively. After SPIO, the CNRs decreased to -21.34 +/-13.07 (P < .001) and -12.44 +/- 14.56, respectively (P < .012). There was a significant linear correlation between the thrombus signal level decrease and the levels of CD68(+) and CD66b(+) cells, pro-MMP-9, and MMP-9 mRNA (P < .05). CONCLUSION: MR imaging allows in vivo demonstration of SPIO uptake at the luminal interface of the thrombus. This uptake is correlated to the abundance of leukocytes. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09090657/-/DC1.

Free-breathing accelerated gadolinium-enhanced MR Angiography in the Diagnosis of Renovascular Disease.

OBJECTIVE: The purpose of this study was to assess the feasibility and accuracy of accelerated free-breathing and breath-hold gadolinium-enhanced MR angiography of the main renal arteries compared with digital subtraction angiography. MATERIALS AND METHODS: Renal MR angiograms and catheter angiograms of 47 patients (19 men, 28 women; mean age, 68.1 +/- 15.1 years; range, 28-86 years) were reviewed. Thirty-one of the patients underwent free-breathing and 16 underwent breath-hold MR angiography with the same accelerated multiphase imaging protocol. Images were analyzed for examination quality, percentage narrowing of the main renal artery, and visibility of the branches. Diagnostic values of MR angiography were calculated with catheter angiography as the standard of reference. RESULTS: Sixty-five arteries, 24 of which (37%) had > 49% narrowing, were evaluated in the free-breathing group, and 37 arteries, six of which (16%) had > 49% narrowing, were evaluated in the breath-hold group. Comparison with digital subtraction angiography showed 100% (24/24) sensitivity and 95% (39/41) specificity for > 49% renal artery stenosis and 88% sensitivity (15/17) and 100% (48/48) specificity for > 74% renal artery stenosis in the free-breathing group. In the breath-hold group, sensitivity was 100% (6/6) and specificity 97% (30/31) for > 49% renal artery stenosis, and sensitivity was 100% (5/5) and specificity 100% (32/32) for > 74% renal artery stenosis. None of the examinations was nondiagnostic for the main renal arteries, but a smaller number of visible arterial tree subdivisions were found in the free-breathing group (average, 3.64 per patient) than in the breath-hold group (average, 5.87 per patient) (p = 0.035). CONCLUSION: Like breath-hold examinations, accelerated free-breathing MR angiographic examinations are feasible and accurate in evaluation of the main renal arteries.

Virtual dissection CT colonography: evaluation of learning curves and reading times with and without computer-aided detection.

PURPOSE: To prospectively evaluate the learning curves and reading times of inexperienced readers who used the virtual dissection reading method for retrospective computed tomographic (CT) colonography data sets, with and without concurrent computer-aided detection (CAD). MATERIALS AND METHODS: An Institutional Review Board approved this study; informed consent was waived. Four radiologists without experience in CT colonography evaluated 100 optical colonoscopy-proved data sets of 100 patients (49 men, 51 women; mean age, 59 years +/- 13 [standard deviation]; range, 21-85 years) by using the virtual dissection reading method. Two readers used concurrent CAD. Data sets were read during five consecutive 1-day sessions (20 data sets per session). Polyp detection and false-positive rates, receiver operating characteristics (ROCs), and reading times were calculated for individual, CAD group, and non-CAD group readings. Diagnostic values were compared by calculating the 95% confidence intervals (CIs) around the relative risk. Areas under ROC curves (AUCs) (Hanley and McNeil for paired analysis and z statistics for unpaired analysis) and reading times (Wilcoxon signed rank test) were compared across the sessions, within each session and for the whole study. RESULTS: The range of detection rates was 79 of 111 (.71 [95% CI: .61, .79]) to 91 of 111 (.82 [95% CI: .73, .88]). The range of false-positive rates was 17 of 111 (.15 [95% CI: .09, .23]) to 22 of 111 (.20 [95% CI: .12, .28]). All readers' AUCs rose from session 1 to session 4; this rise was significant (P < .05) for the non-CAD group. Only during session 1 was the CAD group AUC (.83) higher than the non-CAD group AUC (.54) (P < .05). Comparison of CAD and non-CAD reading times showed no significant difference for the whole study or during each session (P > .05). CONCLUSION: The virtual dissection reading technique allows short learning curves, which may be improved by the concurrent use of CAD, without significant effect on average reading time.

Significance of bowel wall abnormalities at ultrasound in Henoch-Schönlein purpura.

OBJECTIVES: To describe the polymorphism of intestinal ultrasound findings in children with gastrointestinal symptoms of Henoch Schönlein purpura (HSP) and to investigate the clinical relevance of these findings in terms of symptoms and length of hospitalization. PATIENTS AND METHODS: Clinical and ultrasound data from 43 consecutive children with HSP (36 with and 7 without abdominal symptoms) were reviewed. Patients with abdominal symptoms of HSP were divided into 4 groups (0-III) representing at ultrasound normal appearance and differentiated, pseudodifferentiated, and dedifferentiated bowel wall thickening, respectively. The diagnostic value of ultrasound in diagnosing gastrointestinal involvement of HSP (grades I-III) was calculated using as the standard of reference the absence or presence of clinical symptoms. Average duration of symptoms and hospitalization in the 4 groups was compared. RESULTS: The respective sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound for the diagnosis of gastrointestinal involvement of HSP was 83.3%, 100%, 100%, and 53.8%. Groups 0 to III contained, respectively, 5/36 (13.9%), 6/36 (16.7%), 22/36 (61.1%), and 3/36 (8.3%) patients. The groups' average duration of symptoms, respectively, was 2.20 +/- 2.06, 5.67 +/- 1.88, 6.29 +/- .94, and 17.67 +/- 2.66 days, whereas the length of hospitalization, respectively, was 4.80 +/- 2.96, 9.17 +/- 2.70, 11.46 +/- 1.35, and 24.67 +/- 3.82 days. The duration of both symptoms and hospitalization was significantly higher in group III than in the other groups (P < 0.05). CONCLUSIONS: In children with gastrointestinal involvement of HSP, dedifferentiated wall thickening as shown by ultrasound is associated with a poor clinical prognosis.

Sonography in wrist tendon pathology.

Wrist tendons may be affected by a variety of pathologic conditions, including those caused by trauma and overuse, inflammatory and metabolic disorders, or infection. Sonography is a very sensitive means of detecting tendinous pathology because of its spatial resolution and its comparative and dynamic capabilities. Its wide availability makes it the preferred first-line imaging modality in the case of wrist pain. This article reviews the pathologic conditions that may involve the wrist and their sonographic appearances.